Wisconsin votes on recalling its governor Tuesday, and much has already been made of that vote's potential implications beyond the state.

But for now, this historic moment belongs to the 3 million-plus Wisconsinites registered to vote. Most of them are expected to turn out, and those who do will be thinking about the implications for Wisconsin more than the prospects for fallout elsewhere.

In that sense, today's vote is less about the mega issues of 2012 than it is a rerun of the 2010 gubernatorial election, which Republican Scott Walker won by about 125,000 votes (among more than 2 million cast).

For Democratic challenger Tom Barrett, winning the rematch is a challenge that begins at home. Barrett has been mayor of Milwaukee, the state's only big city, since 2004, winning a third term in April with 79 percent of the vote. He needs to translate that mayoral popularity into a stronger showing than he had in his home county and metro area in 2010.

To be sure, Barrett won his own city proper in a landslide in 2010, enabling him to carry Milwaukee County (the city and its immediate ring of suburbs) by a little over 80,000 votes. But Walker, who at the time was the chief elected official (county executive) for Milwaukee County, countered the vote from the city and kept the countywide margin right around where it had been in 2006, when Democratic Gov. Jim Doyle was re-elected.

In 2006, Doyle had ridden that Milwaukee County vote to a narrow win for the overall Milwaukee metro area, superseding the usual Republican blowout in the suburban-exurban counties of Waukesha, Washington and Ozaukee to the west and north.

Two years later, presidential candidate Barack Obama followed that pattern and expanded on it. He swept Milwaukee County by nearly 170,000 votes over John McCain. That was enough to swamp McCain's excellent showing in Waukesha, Washington and Ozaukee (Obama won the four-county metro by about 75,000).

But in 2010, with turnout down dramatically in the city of Milwaukee, Barrett found that the vote in surrounding counties had grown insurmountable. Yes, he carried Milwaukee County by that Doyle-like number. But he was nowhere near the Obama number.

Meanwhile, the vote was going heavily against him in the rest of the metro. Waukesha County alone favored Walker by about 82,000 votes, slightly more than the margin by which Barrett won Milwaukee County. Ozaukee and Washington came piling on, going for Walker by a combined ratio approaching 3-to-1, putting the Republican nearly 50,000 votes ahead for the four-county metro area.

That meant Barrett had to somehow win the contest in the rest of the state, outside the metro area that includes his base. That put tremendous pressure on a handful of other Democratic strongholds outstate. Notable among them: Dane County, home to Madison and the state government and the main campus of the University of Wisconsin. Barrett did well there, winning by about as many votes as he had in Milwaukee County. He also did well enough in blue-collar cities like Janesville, Kenosha and Superior -- but not always well enough to win the corresponding counties.

For his part, Walker was running up big margins in the traditional Republican enclaves in the eastern half of the state, from Walworth in the south to Dodge, Fond du Lac and Winnebago in the east-central part of the state. He had little trouble winning the swing county of Brown, which includes the city of Green Bay.

In short, Barrett simply could not find enough Democratic votes in the rest of the state to make up for losing the four-county Milwaukee metro, where nearly 30 percent of the state's voters live.

In Tuesday's recall, Barrett needs to get much closer to Obama's numbers in the Milwaukee metro, find a way to squeeze even more votes out of Dane and widen his winning margin in outstate counties such as Eau Claire. It would also help if he could flip counties he lost in 2010, including southeastern Racine and Kenosha near the Illinois state line.

That's a tall order. And it explains why even the late polls showing the race getting closer are not shaking the confidence of the governor and his backers.

That means the votes to be counted Tuesday night are likely to follow traditional partisan patterns that have been discernible in the state since the emergence of its modern Democratic Party in the years after World War II. (Prior to that, many of the state's more liberal residents identified with the progressive wing of the Republican Party, led by the legendary LaFollette family).

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